3D Printing Info

Filament comparison

PEI 9085 vs PETG-CF

Compare printing settings, strength, heat resistance, dated prices and sources.

PEI (ULTEM 9085) guideCarbon-fibre PETG (PETG-CF) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PEI 9085 comparisonsMore PETG-CF comparisons
PEI 9085 vs PETG-CF — documented properties and sources
PropertyPEI (ULTEM 9085)HIGHTEMPCarbon-fibre PETG (PETG-CF)PETG
Market snapshot
Listing priceUSD/kg; dated snapshots$309.80/kg median; $220.00–$392.00/kg across 6 dated product listings$29.99/kg median; $16.00–$74.22/kg across 11 dated product listings
Identity & Market
Base polymer / chemistryPolyetherimide, ULTEM 9085 grade — the flame-retardant PEI used for aircraft interiors[1]PETG reinforced with chopped carbon fibre[2][3]
Densityg/cm³1.34 (ISO 1183, 3DXTech) against 1.27 specific gravity on moulded plaques (ASTM D792, Stratasys) — the two suppliers disagree[1][4]1.25 (Bambu Lab) to 1.34 (3DXTech), ISO 1183; Prusament 1.27[2][5][3]
Typical priceUSD/kg1 kg-equivalent spools cluster near 298[6][7][8][9]1 kg-equivalent spools span 16–74; the middle of the market is about 29[2][10][11][12][13][14][15][16]
Price range across brandsUSD/kg220-392 across brands and formats; 3DXTech ThermaX PEI 9085 220 at 2 kg, 3D4Makers 270 at 2 kg, Fiberlogy 298 at 500 g, Kimya 321 at 500 g, IEMAI 3D 385 at 1 kg, 3DXTech CarbonX PEI 9085+CF 392[6][7][8][9][17]16–74 across brands; ELEGOO 16 in a 5 kg pack, Reli3D 17, SUNLU 20, IEMAI 22, Siraya Tech 25, Bambu Lab 32, Sakata 3D 53, 3DXTech 67, Prusament 70, Filament PM 74 on 0.5 kg spools[18][2][6][10][11][12][13][14][15][16]
Market availability1–5Niche, a handful of specialist brands[6][7][8][9]Stocked by most mainstream brands[2][6][10][18]
Spool sizes & diameters1.75 and 2.85 mm; 250 g to 2 kg spools, plus Stratasys canisters[6][9][4]1.75 and 2.85 mm; 0.75 and 1 kg spools[6][2]
Typical applicationsAircraft interior parts and rail rolling stock, where the flame, smoke and toxicity rating is the requirement[1]Stiff functional parts and fixtures where PETG's toughness is traded for rigidity and a matte finish[2][3]
Diameter tolerance± mmNot documented±0.02 (Prusament)[3]
Printing Parameters
Nozzle temperature°CNot documented240–270 (Bambu Lab); 265 ± 10 (Prusament)[2][3]
Bed temperature°C130–140 (3DXTech)[1]65–75 (Bambu Lab); 90 ± 10 (Prusament)[2][3]
Enclosure / chamber requirement1–5Actively heated chamber required[19][20]Open frame fine; draught shield helps — Bambu Lab specifies a 35–50 °C chamber[2]
Recommended chamber temperature°CNot documented35–50 (Bambu Lab)[2]
Part cooling fanNot documented0–60 % (Bambu Lab); 50 % (Prusament)[2][3]
Bed surface & adhesion aidNot documentedTextured PEI or engineering plate with glue (Bambu Lab)[2]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sNot documented11.5 on My Tech Fun's Bambu Lab PETG-CF profile[21]
Warping tendency1–5Severe — heated chamber needed[19]Not documented
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive[2]
Stringing / oozing tendency1–5Not documentedSlight — the fibre reduces stringing against unfilled PETG[2][22]
Overall printing difficulty1–5Expert / industrial hardware only[19][20]Intermediate — dry filament and a tuned profile; hardened nozzle mandatory[2]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely for unfilled grades, but brass softens near these nozzle temperatures — hardened or plated hot ends are the norm[19]Hardened steel required[2]
Abrasiveness1–5Non-abrasive when unfilled[1]Highly abrasive — standard CF composite[2]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; 3DXTech lists no special nozzle concerns but a mandatory 120 °C pre-dry before every print[23]Moderate — needs dry filament and a clean nozzle; 3DXTech specifies a hardened 0.4 mm minimum nozzle and 0.25 mm layers or higher, and Prusa lists composites as a higher clogging risk[24][25]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[22]
Hotend requirementNot documentedHardened steel nozzle; no high-temperature hot-end needed[2][22]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Not documentedLow — 0.30 % saturated at 25 °C / 55 % RH (Bambu Lab)[2]
Equilibrium moisture content at ~50 % RH%Not documented0.30 saturated at 25 °C / 55 % RH (Bambu Lab); Prusa measures 0.10 after 7 days at 22 % RH[2][3]
Drying temperature & timeNot documented65 °C for 8 h (Bambu Lab)[2]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[26]
Effect of moisture on strengthNo dry-versus-conditioned figures are published; 3DXTech mandates a 120 °C, 4 h pre-dry before every print because trapped water flashes to steam at these nozzle temperatures[23]No dry-versus-conditioned figures published; Bambu Lab states PETG-CF must be properly dried before printing and stored dry after use[2][26]
Storage requirementNot documentedSealed with desiccant; Bambu Lab says store dry after use[2][26]
Mechanical Properties
Tensile strength (XY)MPa63-77 at break (printed XZ, ASTM D638, Stratasys F900/F3300/Fortus 450mc, three tips and two colours); 54 (printed XY, ISO 527, 3DXTech)[4][1]35 ± 5 (Bambu Lab) and 47 ± 2 at yield (Prusament) printed XY, ISO 527; 56 at break for 3DXTech[2][3][5]
Young's modulusMPa2040-2540 (printed XZ, ASTM D638, Stratasys); 2050 (printed XY, ISO 527, 3DXTech)[4][1]2460 ± 230 (Bambu Lab) and 1700 (Prusament) printed XY, ISO 527[2][3]
Elongation at break%5.4-9.1 at break (printed XZ, ASTM D638, Stratasys); 1.9-4.3 in ZX; 3DXTech quotes 3 (ISO 527)[4][1]4.3 at yield (Prusament, printed XY, ISO 527); 3 at break for 3DXTech[3][5]
Flexural strengthMPa104-116 at break (printed XZ, ASTM D790 Procedure A, Stratasys); 72-98 in ZX; 3DXTech quotes 90 (ISO 178)[4][1]68 ± 3 printed horizontal, ISO 178 (Prusament)[3]
Flexural modulusMPa2400-2550 (printed XZ, ASTM D790, Stratasys F900 T16 and T16A) against 2120-2130 in ZX; 3DXTech quotes 2170 (ISO 178)[4][1]2300 printed horizontal, 3100 printed vertical, ISO 178 (Prusament)[3]
Other impact dataIzod notched 88.5-140 J/m XZ against 37-80 J/m ZX; unnotched 647-2260 J/m XZ against 169-633 J/m ZX (printed, ASTM D256/D4812, Stratasys, across three printers and three tips)[4]Charpy unnotched 29 ± 6 printed horizontal and 43 ± 8 printed vertical (Prusament, ISO 179-1); Izod 4.91 kJ/m² on My Tech Fun bars[3][21]
Layer adhesion / Z tensileMPa39-63 at break (printed ZX, ASTM D638, Stratasys); the low end is the F900 T16 baseline, the high end the F3300 N500 hot end[4]29 ± 4 printed Z (Bambu Lab, ISO 527); 18 ± 3 by Prusa's interlayer adhesion test; 10.7 on My Tech Fun bars[2][3][21]
Brittleness1–5Brittle — snaps with little warning[1]Brittle — snaps with little warning[5]
Hardness (scale-specific)Shore A / Shore D / RockwellRockwell M110 / R126 on extruded PEI stock (ASTM D785)[27]77 Shore D (Prusa Polymers method)[3]
Creep resistance / sustained load1–5Excellent — holds load for years. Printed ZX coupons keep 87 % of room-temperature tensile strength at 104 °C and 70 % at 132 °C (ASTM D638); extruded PEI stock is rated 170 °C long-term service[4][27]Below average — a 12 mm bar sagged to 16.4 mm over 5 days at 1.25 kg, less than plain PETG's 19.4[21]
Fatigue / repeated-flex resistance1–5Not documentedModerate — no CF-grade S-N curve; unfilled printed PETG ran 79 000–193 000 cycles at 30 % of tensile strength[28]
Elasticity / flexibility1–5Rigid[1]Rigid[2]
Z strength as % of XY%56-86 (Stratasys ZX against XZ tensile at break, ASTM D638, across F900/F3300/Fortus 450mc and T16/T20/T40A tips); 58 on the F900 T16 baseline[4]83 (Bambu Lab, printed Z against XY tensile)[2]
Thermal Properties
HDT at 0.45 MPa°C158 (printed XY, ISO 75 at 0.45 MPa, 3DXTech) to 178 (printed XY 178.2 and ZX 178.4, ASTM D648 Method B at 66 psi, Stratasys); moulded 176.9[1][4]74 (Bambu Lab) and 96 (Prusament), ISO 75 at 0.45 MPa[2][3]
HDT at 1.8 MPa°C170-173 (printed XY 170.2 and ZX 172.6, ASTM D648 Method B at 264 psi); moulded 172.9[4]68 (Bambu Lab) and 80 (Prusament), ISO 75 at 1.8 MPa[2][3]
Glass transition (Tg)°C177 (moulded plaque, ASTM D7426 inflection point, Stratasys); 186 (DSC, 3DXTech)[4][1][29]68 (Bambu Lab) and 80 (3DXTech), DSC[2][5]
Melting point / Vicat°CNot documented225 melting (Bambu Lab, DSC) — the carbon fibre lets the PET fraction crystallise[2]
Continuous service temperature°C170 long-term service on extruded PEI stock, converted from 338 °F; 200 short term[27]77 — loaded bars begin to move at this temperature, against 61 for Bambu Lab PETG Basic[21]
Thermal expansion (CTE)µm/m·K44.9 (printed XY, -50 to 80 °C, ASTM E831), falling to 31.4 over 80-160 °C; ZX gives 44.5 over -50 to 60 °C. Black pigment raises it to 51.9[4]Not documented
Flammability / UL 94UL 94 V-0 at 1.5 mm on the base resin. Printed parts are tested to 14 CFR 25.853, BSS 7238 and 7239 and AITM 2.0007B and 3.0005 covering 60 s and 12 s vertical burn, 15 s horizontal burn, smoke density, toxic gas emission and OSU heat release[1][4]Flammable; no UL 94 rating published[2]
Environment & Chemical
UV resistance1–5Good — years with some colour shift. 1000 h of QUV cycling to ASTM G154 left printed ZX coupons at 55.5 MPa yield against 56.0 unexposed, with elongation and modulus unchanged[4]Moderate — a season or two; the carbon fibre does not add UV stabilisation[30]
Chemical resistanceNot documentedWithstands acids, alkalis, oils and UV exposure, as for unfilled PETG[30]
Food contactNot documentedNot certified for food contact[30]
Biodegradability / compostabilityNot documentedNot biodegradable[30]
RecyclabilityNot documentedFibre-filled PETG is not accepted in household plastic collection[30]
Electrical & ESD propertiesNot documentedSurface resistance above 10⁹ ohm/sq — carbon fibre at this loading is not static-dissipative (3DXTech)[5]
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised. None of these polymers was in the chamber study, and all are processed far above the temperatures it covered[31]Moderate — measurable VOCs and UFPs, ventilation advised[31]
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[31]Open a window / occasional ventilation[31]
Dust & fibre handling hazardNot documentedCarbon fibre is bound in the matrix; sanding dust should not be inhaled[5]
Post-Processing
Sanding & machiningNot documentedSands to a matte finish more readily than unfilled PETG[22]
Gluing & solvent weldingNot documentedCyanoacrylate; no common solvent welds it[22]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[22]
Support material pairingNot documentedSupport for PLA or its own material (Bambu Lab)[2]
Dimensional accuracy & detailNot documentedMatte finish hides layer lines; stringing is reduced against unfilled PETG[2]
Solvents & Solubility
Soluble inChlorinated hydrocarbons — dichloromethane and chloroform — are solvents for polyetherimide. Laboratory reagents.[32][33]No common workshop solvent; dichloromethane — a carcinogen — dissolves the matrix surface, 1,2-dichloroethane destroys it in a week.[34][35]
Softened or crazed byAcetone, MEK, benzene, toluene and butyl acetate craze or stress-crack it; alcohols, fuels and dilute acids do not.[33][32]Acetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[34]
Solvent welding & smoothing agentDichloromethane is the only welding route, and it is a controlled carcinogen rather than a workshop material.[32][33]Dichloromethane reaches only the resin, so the fibre is left standing proud of the surface. Controlled carcinogen.[35]

Material entries describe families or representative grades, not an interchangeable specification for every spool. Test methods, orientations and conditions may differ. Unknown values are marked “Not documented”. Prices and source dates remain historical snapshots; check the linked guide for product details. Differences highlight text, not a universal winner.

Sources for this comparison

  1. ThermaX PEI 9085 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  2. Bambu Filament Technical Data Sheet — PETG-CF Bambu Lab · 2026-08 · tds
  3. Prusament PETG Carbon Fiber Technical Datasheet Prusa Polymers · 2026-08 · tds
  4. ULTEM 9085 Resin — FDM Material Data Sheet Stratasys · 2026-04 · tds
  5. CarbonX Carbon Fiber PETG Technical Data Sheet 3DXTech · 2026-08 · tds
  6. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  7. Kimya PEI-9085 Natural 2.85 mm 500 g igo3d · 2026-08 · vendor
  8. Fiberlogy PEI 9085 Natural, 1.75 mm / 500 g 3DJAKE · 2026-08 · vendor
  9. 3D4Makers product catalogue 3D4Makers · 2026-08 · vendor
  10. Printed Solid product catalogue Printed Solid · 2026-08 · vendor
  11. SUNLU PETG-CF (PETG Carbon Fiber) 3D Printer Filament 1 kg SUNLU · 2026-08 · vendor
  12. Fibreheart PETG-CF Pro Filament product page Siraya Tech · 2026-08 · vendor
  13. IEMAI CF-PETG 3D Printing Filament product page IEMAI 3D · 2026-08 · vendor
  14. Reli3D Carbon Fiber PETG Filament 1.75 mm, 1 kg Reli3D (Amazon US) · 2026-08 · vendor
  15. PET-G CF15 Sakata 3D Filaments · 2026-08 · vendor
  16. Filament PM CFJet technical data sheet (TDS CFJet ENG.pdf) Filament PM (Plasty Mladec) · 2026-08 · tds
  17. IEMAI 3D PEI 9085 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  18. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  19. Prusament PEI 1010 Technical Datasheet v1.0 Prusa Polymers · 2024-09 · tds
  20. Prusament PEI 1010 — material page Prusa Polymers · 2026-08 · doc
  21. BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  22. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  23. THERMAX PEI 9085 — product page (print recommendations) 3DXTech · 2026-08 · doc
  24. CARBONX PETG+CF — product page (print recommendations) 3DXTech · 2026-08 · doc
  25. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  26. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  27. TECAPEI natural (PEI) — stock shape properties Ensinger · 2026-08 · tds
  28. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  29. ThermaX PEI 1010 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  30. PETG — material basics Polymaker Wiki · 2026-08 · doc
  31. Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments (Azimi et al.) Environmental Science & Technology 50(3) 1260-1268 · 2016-01 · paper
  32. Radel PPSU, Veradel PESU, Acudel modified PPSU Design Guide — environmental stress cracking tables Solvay Specialty Polymers · 2026-08 · tds
  33. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  34. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  35. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc